Red cell enzyme defects as nondiseases and as diseases

Abstract

Certain important conclusions may be drawn: It is quite clear that many patients with chronic hemolytic anemia of unknown origin do not have a detectable red cell enzyme defect; this includes those who are quite young and in whom there is a strong likelihood that the anemia is hereditary in origin. There seems to be little question that G-6-PD deficiency and pyruvate kinase deficiency are the most common of the enzyme deficiencies that are detected. Much less common than these two defects, but clearly more prevalent than any of the other remaining defects, are deficiencies of glucose phosphate isomerase and pyrimidine 5'-nucleotidase activity. It is particularly notable that although assays for pyrimidine 5'-nucleotidase were performed on only 80 samples, 5 cases of this relatively rarely reported enzyme deficiency were encountered. Appreciable numbers of blood samples from patients in whom the diagnosis of pyruvate kinase deficiency had been excluded on the basis of tests carried out in commercial or other laboratories were, in reality, clearly pyruvate-kinase-deficient. Study of this relatively large group of patients with hemolytic anemia, believed possibly to be due to enzyme deficiencies, did not yield a single patient with glutathione reductase deficiency or with 6-phosphogluconic dehydrogenase deficiency.